Now that I'm thinking about it this more... What do you guys think about airline mileage cards? Are those better?

Maybe i can sign up for two other cards... Hilton rewards to stay at hilton hotels, continue to use my SPG to stay at SPG hotels, and then the air mileage for everyday purchases.

Spend $10,000 a year on Hilton just to get those complimentary hotels, and then rest on air mileage card...